| // Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| #include "vm/unicode.h" |
| |
| #include "vm/allocation.h" |
| #include "vm/globals.h" |
| #include "vm/object.h" |
| |
| namespace dart { |
| |
| static const uint8_t kTrailBytes[256] = { |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, |
| 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, |
| 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, |
| 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, |
| 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 0, 0 |
| }; |
| |
| |
| static const uint32_t kMagicBits[7] = { |
| 0, // padding |
| 0x00000000, |
| 0x00003080, |
| 0x000E2080, |
| 0x03C82080, |
| 0xFA082080, |
| 0x82082080 |
| }; |
| |
| |
| // Minimum values of code points used to check shortest form. |
| static const uint32_t kOverlongMinimum[7] = { |
| 0, // padding |
| 0x0, |
| 0x80, |
| 0x800, |
| 0x10000, |
| 0xFFFFFFFF, |
| 0xFFFFFFFF |
| }; |
| |
| |
| static bool IsTrailByte(uint8_t code_unit) { |
| return (code_unit & 0xc0) == 0x80; |
| } |
| |
| |
| // Returns true if the code point is a high- or low-surrogate. |
| static bool IsSurrogate(uint32_t code_point) { |
| return (code_point & 0xfffff800) == 0xd800; |
| } |
| |
| |
| // Returns true if the code point value is above Plane 17. |
| static bool IsOutOfRange(uint32_t code_point) { |
| return code_point > 0x10FFFF; |
| } |
| |
| |
| // Returns true if the byte sequence is ill-formed. |
| static bool IsNonShortestForm(uint32_t code_point, size_t num_bytes) { |
| return code_point < kOverlongMinimum[num_bytes]; |
| } |
| |
| |
| // Returns a count of the number of UTF-8 trail bytes. |
| intptr_t Utf8::CodePointCount(const char* str, intptr_t* width) { |
| bool is_two_byte_string = false; |
| bool is_four_byte_string = false; |
| intptr_t len = 0; |
| for (; *str != '\0'; ++str) { |
| uint8_t code_unit = *str; |
| if (!IsTrailByte(code_unit)) { |
| ++len; |
| } |
| if (code_unit > 0xC3) { // > U+00FF |
| if (code_unit < 0xF0) { // < U+10000 |
| is_two_byte_string = true; |
| } else { |
| is_four_byte_string = true; |
| } |
| } |
| } |
| if (is_four_byte_string) { |
| *width = 4; |
| } else if (is_two_byte_string) { |
| *width = 2; |
| } else { |
| *width = 1; |
| } |
| return len; |
| } |
| |
| |
| // Returns true if str is a valid NUL-terminated UTF-8 string. |
| bool Utf8::IsValid(const char* str) { |
| intptr_t i = 0; |
| while (str[i] != '\0') { |
| uint32_t ch = str[i] & 0xFF; |
| intptr_t j = 1; |
| if (ch >= 0x80) { |
| uint8_t num_trail_bytes = kTrailBytes[ch]; |
| bool is_malformed = false; |
| for (; j < num_trail_bytes; ++j) { |
| if (str[i + j] != '\0') { |
| uint8_t code_unit = str[i + j]; |
| is_malformed |= !IsTrailByte(code_unit); |
| ch = (ch << 6) + code_unit; |
| } else { |
| return false; |
| } |
| } |
| ch -= kMagicBits[num_trail_bytes]; |
| if (!((is_malformed == false) && |
| (j == num_trail_bytes) && |
| !IsOutOfRange(ch) && |
| !IsNonShortestForm(ch, j) && |
| !IsSurrogate(ch))) { |
| return false; |
| } |
| } |
| i += j; |
| } |
| return true; |
| } |
| |
| |
| intptr_t Utf8::Length(int32_t ch) { |
| if (ch <= kMaxOneByteChar) { |
| return 1; |
| } else if (ch <= kMaxTwoByteChar) { |
| return 2; |
| } else if (ch <= kMaxThreeByteChar) { |
| return 3; |
| } |
| ASSERT(ch <= kMaxFourByteChar); |
| return 4; |
| } |
| |
| |
| intptr_t Utf8::Length(const String& str) { |
| intptr_t length = 0; |
| for (intptr_t i = 0; i < str.Length(); ++i) { |
| int32_t ch = str.CharAt(i); |
| length += Utf8::Length(ch); |
| } |
| return length; |
| } |
| |
| |
| intptr_t Utf8::Encode(int32_t ch, char* dst) { |
| static const int kMask = ~(1 << 6); |
| if (ch <= kMaxOneByteChar) { |
| dst[0] = ch; |
| return 1; |
| } |
| if (ch <= kMaxTwoByteChar) { |
| dst[0] = 0xC0 | (ch >> 6); |
| dst[1] = 0x80 | (ch & kMask); |
| return 2; |
| } |
| if (ch <= kMaxThreeByteChar) { |
| dst[0] = 0xE0 | (ch >> 12); |
| dst[1] = 0x80 | ((ch >> 6) & kMask); |
| dst[2] = 0x80 | (ch & kMask); |
| return 3; |
| } |
| ASSERT(ch <= kMaxFourByteChar); |
| dst[0] = 0xF0 | (ch >> 18); |
| dst[1] = 0x80 | ((ch >> 12) & kMask); |
| dst[2] = 0x80 | ((ch >> 6) & kMask); |
| dst[3] = 0x80 | (ch & kMask); |
| return 4; |
| } |
| |
| |
| intptr_t Utf8::Encode(const String& src, char* dst, intptr_t len) { |
| intptr_t pos = 0; |
| for (intptr_t i = 0; i < src.Length(); ++i) { |
| intptr_t ch = src.CharAt(i); |
| intptr_t num_bytes = Utf8::Length(ch); |
| if (pos + num_bytes > len) { |
| break; |
| } |
| Utf8::Encode(ch, &dst[pos]); |
| pos += num_bytes; |
| } |
| return pos; |
| } |
| |
| |
| intptr_t Utf8::Decode(const char* src, int32_t* dst) { |
| uint32_t ch = src[0] & 0xFF; |
| uint32_t i = 1; |
| if (ch >= 0x80) { |
| uint32_t num_trail_bytes = kTrailBytes[ch]; |
| bool is_malformed = false; |
| for (; i < num_trail_bytes; ++i) { |
| if (src[i] != '\0') { |
| uint8_t code_unit = src[i]; |
| is_malformed |= !IsTrailByte(code_unit); |
| ch = (ch << 6) + code_unit; |
| } else { |
| *dst = -1; |
| return 0; |
| } |
| } |
| ch -= kMagicBits[num_trail_bytes]; |
| if (!((is_malformed == false) && |
| (i == num_trail_bytes) && |
| !IsOutOfRange(ch) && |
| !IsNonShortestForm(ch, i) && |
| !IsSurrogate(ch))) { |
| *dst = -1; |
| return 0; |
| } |
| } |
| *dst = ch; |
| return i; |
| } |
| |
| |
| template<typename T> |
| static bool DecodeImpl(const char* src, T* dst, intptr_t len) { |
| intptr_t i = 0; |
| intptr_t j = 0; |
| intptr_t num_bytes; |
| for (; src[i] != '\0' && j < len; i += num_bytes, ++j) { |
| int32_t ch; |
| num_bytes = Utf8::Decode(&src[i], &ch); |
| if (ch == -1) { |
| return false; // invalid input |
| } |
| dst[j] = ch; |
| } |
| if (src[i] != '\0' && j == len) { |
| return false; // output overflow |
| } |
| return true; // success |
| } |
| |
| |
| bool Utf8::Decode(const char* src, uint8_t* dst, intptr_t len) { |
| return DecodeImpl(src, dst, len); |
| } |
| |
| |
| bool Utf8::Decode(const char* src, uint16_t* dst, intptr_t len) { |
| return DecodeImpl(src, dst, len); |
| } |
| |
| |
| bool Utf8::Decode(const char* src, uint32_t* dst, intptr_t len) { |
| return DecodeImpl(src, dst, len); |
| } |
| |
| } // namespace dart |